Direct detection of Rydberg–Rydberg millimeter-wave transitions in a buffer gas cooled molecular beam

Zhou, Yan; Grimes, David; Barnum, Timothy J.; Patterson, David; Coy, Stephen L.; Klein, E.; Muenter, J. S.; Field, Robert W.

doi:10.1016/j.cplett.2015.10.010

Cited by 22 publications

(16 citation statements)

References 49 publications

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“…2, summarized here. 2,[40][41][42][43] Barium atoms are generated by ablation of a barium target with a ≤50 mJ pulse of the 1064 nm fundamental of a Nd:YAG laser, focused to a ∼1 mm 2 spot size. We allow the Q-switch to remain open after the initial laser pulse, which causes postablation localized melting of the Ba target.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Rydberg states of molecules are a relatively unexplored area of molecular physics. High resolution spectra of molecular Rydberg states will enable precision measurements of the properties of molecular cations, [1][2][3][4][5][6] highly efficient Stark slowing and trapping of neutral molecules, [7][8][9][10][11] and identification of the physical mechanisms of electron-ion energy transfer and reaction pathways in simple systems. [12][13][14][15][16][17][18][19][20][21][22] However, for nearly all molecules, the ionization threshold lies at a much higher energy than the dissociation threshold.…”

Section: Introductionmentioning

confidence: 99%

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Coherent laser-millimeter-wave interactions en route to coherent population transfer

Grimes

Barnum

Zhou

et al. 2017

The Journal of Chemical Physics

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We demonstrate coherent two-photon population transfer to Rydberg states of barium atoms using a combination of a pulsed dye laser and a chirped-pulse millimeter-wave spectrometer. Numerical calculations, using a density matrix formalism, reproduce our experimental results and explain the factors responsible for the observed fractional population transferred, optimal experimental conditions, and possibilities for future improvements. The long coherence times associated with the millimeter-wave radiation aid in creating coherence between the ground state and Rydberg states, but higher-coherence laser sources are required to achieve stimulated Raman adiabatic passage and for applications to molecules.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coherent laser-millimeter-wave interactions en route to coherent population transfer

Grimes

Barnum

Zhou

et al. 2017

The Journal of Chemical Physics

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“…We generate an atomic beam of barium atoms using a neon buffer gas cooled atomic beam similar to that described in reference [29] and summarized briefly here. Barium atoms are generated by ablation of a metal target inside a buffer gas cell with 50 mJ/pulse of the 1064 nm fundamental of a Q-switched Nd:YAG laser focused to a 1 mm 2 spot size.…”

Section: Arxiv:160403005v1 [Physicsatom-ph] 11 Apr 2016mentioning

confidence: 99%

“…Previous studies of collective effects in ensembles of Rydberg states have relied on state-selective field ionization detection in order to infer indirectly that superradiance has occurred [15,[17][18][19]. Direct detection of the emitted electric field was achieved in cavity based maser experiments in the 1980s, but was sensitive only to the intensity of the emission, not to its frequency or phase [20,21].Recent improvements in mm-wave technology [22][23][24][25][26] and atomic beam sources [27][28][29] have enabled direct observation of superradiance in a single shot. In this letter, we report direct heterodyne detection of the timedependent emitted electric field that arises from superradiance in a sample of Barium Rydberg atoms.…”

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Direct single-shot observation of millimeter-wave superradiance in Rydberg-Rydberg transitions

et al. 2017

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We have directly detected millimeter wave (mm-wave) free space superradiant emission from Rydberg states (n ∼ 30) of barium atoms in a single shot. We trigger the cooperative effects with a weak initial pulse and detect with single-shot sensitivity and 20 ps time resolution, which allows measurement and shot-by-shot analysis of the distribution of decay rates, time delays, and timedependent frequency shifts. Cooperative line shifts and decay rates are observed that exceed values that would correspond to the Doppler width of 250 kHz by a factor of 20 and the spontaneous emission rate of 50 Hz by a factor of 10 5 . The initial superradiant output pulse is followed by evolution of the radiation-coupled many-body system toward complex long-lasting emission modes. A comparison to a mean-field theory is presented which reproduces the quantitative time-domain results, but fails to account for either the frequency-domain observations or the long-lived features.Superradiance is an effect in which emitters radiate collectively and coherently due to constructive interference between electric dipoles that communicate with each other via a shared radiation field [1]. Subradiance is exactly the opposite -a collective inhibition of radiation due to destructive interference between the radiation from an array of dipoles [2,3]. These cooperative phenomena provide insights into fundamental many-body physics [4][5][6] and suggest applications ranging from quantum information storage [7][8][9] to narrow linewidth lasers [10][11][12][13].The large electric dipole transition moments and long wavelengths associated with Rydberg-Rydberg transitions make these transitions natural candidates for observing collective effects at relatively low atom number densities (ρ ∼ 10 6 cm −3 ). Hydrogenic scaling rules show that, for ∆n = 1 (where n is the principal quantum number), the transition dipole moment between Rydberg states scales as µ ∝ n 2 and the wavelength scales as λ ∝ n 3 . The transition dipole moment controls only the individual atom spontaneous decay rate, which is independent of density. Collective effects, however, scale in multiples of the spontaneous decay rate. The multiplicative factors scale as the optical depth (OD = ρλ 2 L, where ρ is the density and L is the length of the sample) [6] or the relative density (RD = ρλ 3 ) [14]. Thus, these two scaling rules result in strong collective effects at several orders of magnitude lower densities than between valence states of atoms or molecules. Superradiant emission is also focused primarily on the transition with the smallest ∆n allowed by the ∆ = ±1 angular momentum selection rule [15]. For Rydberg states with n ∼ 30, ∆n = 1 transitions lie at ∼300 GHz (λ ∼ 1mm) and have transition moments on the order of 500 debye [16].Typically, the total number of Rydberg state atoms in a single experiment has been too small to permit direct detection of the emitted electric field. Previous studies of collective effects in ensembles of Rydberg states have relied on state-selective field ioni...

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The Hunt for Elusive Molecules: Insights from Joint Theoretical and Experimental Investigations

Martin-Drumel

Baraban

Changala

et al. 2019

Chemistry A European J

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Rotational spectroscopy is an invaluable tool to unambiguously determine the molecular structure of a species, and sometimes even to establish its very existence. This article illustrates how experimental and theoretical state‐of‐the‐art tools can be used in tandem to investigate the rotational structure of molecules, with particular emphasis on those that have long remained elusive. The examples of three emblematic species—gauche‐butadiene, disilicon carbide, and germanium dicarbide—highlight the close, mutually beneficial interaction between high‐level theoretical calculations and sensitive microwave measurements. Prospects to detect other elusive molecules of chemical and astronomical interest are discussed.

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Direct detection of Rydberg–Rydberg millimeter-wave transitions in a buffer gas cooled molecular beam

Cited by 22 publications

References 49 publications

Coherent laser-millimeter-wave interactions en route to coherent population transfer

Coherent laser-millimeter-wave interactions en route to coherent population transfer

Direct single-shot observation of millimeter-wave superradiance in Rydberg-Rydberg transitions

The Hunt for Elusive Molecules: Insights from Joint Theoretical and Experimental Investigations

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